Trileaflet Valve for VAD Use with Purged Sinus

Clinical applications of ventricle assist devices continue to be problematic due to thromboembolic complications. The problem originates mainly at the valves, which are usually made of an antithrombogenic material, such as cross-linked bovine pericardium. However, wherever the blood flow is stagnant or forms a recirculation region, a thrombus is likely to form. A similar blood flow is found in the space between the housing of the valve and the leaflets, the so-called valve sinus. Consequently, thrombi are often generated in this region. The novel valve design presented in this article avoids the formation of stagnant flow in the valve sinus during systole by a purge flow. This flow is taken from the main flow through the valve and is directed into each sinus region. The effect is achieved by perforation of the valve sinus with a small orifice at the bottom of the sinus. The purge flow effect is investigated with the computational fluid dynamics (CFD) method. The simulation shows that the purge flow effectively increases flow in the valve sinuses.